(1) Field of the Invention
The present invention relates to a technique of controlling reproduction of a content which is stream data divided into a plurality of replay segments, and more specifically, it relates to the skip function thereof.
(2) Description of the Prior Art
In recent years, services for distributing users with multimedia contents (hereinafter referred to as contents) that include commercial messages (CM) of sponsors of the contents at no extra charge have been offered. A user can listen and watch a distributed content using a content reproducing apparatus, such as a personal computer and a mobile device. The distributed content is divided into a plurality of replay segments, and each of the plurality of replay segment includes a part of the content with a certain degree of cohesiveness, such as each scene from the main content.
A content reproducing apparatus is provided with a skip function as one of functions related to content reproduction. When the content reproducing apparatus receives a skip instruction from a user during a content is being reproduced, the content reproducing apparatus stops reproducing data of a replay segment that is being reproduced and starts reproducing data of a succeeding replay segment. Further, when the content reproducing apparatus receives an instruction from the user that specifies the replay segment to be reproduced after skipping, the content reproducing apparatus starts reproducing data of the specified replay segment. Utilizing the skip function enables a user to listen and watch the contents effectively in a short period of time, without reproducing content that the user does not wish to listen nor watch.
On the other hand, the skip function can be disadvantageous for content providers, because it is possible that, by utilizing the skip function, users listen and watch contents without reproducing replay segments for CMs of sponsors. If a CM is skipped without being reproduced too often, it becomes highly probable that the sponsor considers the advertising effectiveness of the CM is low and thus stops sponsoring. A method disclosed in Japanese Laid-Open Patent Application No. H10-164550 provides one solution to the above problem. H10-164550 teaches a mechanism in which a key for decoding an encrypted main content is embedded in data of a CM and the key can be obtained only by reproducing the entire data of the CM.
However, the method disclosed in H10-164550 forces a user to reproduce the CM in order to listen and watch the main content, even if the user is not interested in the CM included in the content at all. Users will not be amused by such forced CMs, and sponsors also try to avoid a sense of discomfort being caused in the users while listening and watching their CMs as much as possible.
Moreover, in a case in which the method taught in H10-164550 is applied to a content distribution service that distributes dynamically arranged content, a content distributing server executes an encrypting process to the arranged content. Because the encrypting process is required to be executed in real time, such a method increases the load to the content distributing server.